Related Applications
This application is related to U.S. patent application Ser. No. 08/155,314, titled FORCED ENGAGEMENT LOGIC, filed Sep. 22, 1993, now U.S. Pat. No. 5,429,559 and assigned to the same assignee, Eaton Corporation, as this application.
Field of the Invention
This invention relates to vehicular automatic or partially automatic compound mechanical transmission systems having a main section and an auxiliary section connected in series therewith and, in particular, to automated compound mechanical transmission systems of the range type wherein two selectable range ratios are engaged by a double-acting synchronized jaw clutch.
More particularly, the present invention relates to a control system/method which enhances recovery from unintended non-engagement conditions in the synchronized range section of an automated mechanical compound range-type transmission.
Description of the Prior Art
Fully automatic transmission systems, both for heavy-duty vehicles such as heavy-duty trucks, and for automobiles, that sense throttle openings or positions, vehicle speeds, engine speeds, transmission shaft speeds and the like, and automatically shift the vehicle transmission in accordance therewith, are well known in the prior art. Such fully automatic change gear transmission systems include automated transmissions wherein pressurized fluid is utilized to frictionally engage one or more members to other members or to a ground to achieve a selected gear ratio as well as automated mechanical transmissions utilizing electronic and/or pneumatic logic and actuators to engage and disengage mechanical (i.e., positive) clutches to achieve a desired gear ratio. Examples of such transmissions may be seen by reference to U.S. Pat. Nos. 3,961,546; 4,081,065 and 4,361,060, the disclosures of which are incorporated herein by reference.
Semi-automatic transmission systems utilizing electronic control units which sense throttle position, engine, input shaft, main shaft, output shaft and/or vehicle speed, and utilize automatically controlled fuel throttle devices, gear shifting devices and/or master clutch operating devices to substantially fully automatically implement operator manually selected transmission ratio changes are known in the prior art. Examples of such semi-automatic transmission systems may be seen by reference to U.S. Pat. Nos. 4,425,620; 4,631,679 and 4,648,290, the disclosures of which are incorporated herein by reference.
Semi-automatic shift implementation systems/methods for mechanical transmission systems for use in vehicles having a manually only controlled engine throttle means and/or a manually only controlled master clutch, have been proposed. Such systems may be seen by reference to U.S. Pat. Nos. 5,053,959; 5,053,961; 5,053,962; 5,063,511; 5,050,079; 5,081,588; 5,089,962 and 5,105,357, the disclosures of which are incorporated herein by reference.
For heavy duty vehicles, such as trucks and tractor/semi-trailer vehicles, compound fully or partially automated transmissions comprising a main section connected in series with a range, splitter or combined range and splitter auxiliary section, are typically utilized to provide the required 9, 10, 12, 13, 16, 18 or more forward speed ratios. Typically, the range auxiliary sections utilize a two-sided double-acting synchronized jaw clutch assembly to engage a selected one of the two selectable range section ratios.
In an automated compound mechanical transmission, especially an automated compound transmission of the range type or the combined splitter and range type, it is important to provide a procedure for engaging or reengaging the selected range ratio, while avoiding crash-through shifts, upon sensing that range section did not complete engagement or has come out of engagement (i.e., upon sensing an unintended, not-engaged range section condition).